The present invention relates to a capacitor and manufacturing method thereof.
Conventional small-sized capacitors are known in which an electrode section composed of a thin-film dielectric layer or a metal film is formed on a relatively rigid substrate such as ceramic or an epoxy resin. However, it is possible to reduce a thickness of the thin-film dielectric layer or electrode section of such a capacitor, whereas a substrate of this kind may be damaged or broken if its thickness is reduced below a certain value (e.g. 0.5 mm). Thus, there is a limit on a reduction in the thickness of such a capacitor. It has been difficult to use this capacitor in a product of thickness smaller than 1 mm.
To deal with this, a film-like flexible substrate has been provided which is composed of a very flexible organic resin substrate such as polyimide which has a thickness of 0.1 mm or smaller as disclosed in, for example, Japanese Patent Laid-Open No. 11-97287. Even if the flexible substrate is made thinner, a capacitor of this kind is not damaged or broken because the flexible substrate itself can be bent. Accordingly, the thickness of the substrate and thus of the entire capacitor can be reduced. Consequently, this capacitor can be used in an IC card of thickness about 1 mm or a thinner product.
A capacitor of this kind is manufactured, for example, as shown in FIGS. 23(a) to 23(c). First, as shown in FIG. 23(a), a lower electrode 103 and an external leader electrode 104 are formed so as to cover the opposite sides and top surface of a film-like very flexible substrate 101 and to have a gap 102 between themselves so that the electrodes 103 and 104 are not electrically connected together. Then, a dielectric 105 is formed on the top surfaces of the lower electrode 103 and the external leader electrode 104 so as to extend across these electrodes. Subsequently, as shown in FIG. 23(b), a hole 105a for a contact hole is formed through the dielectric 105 at a position corresponding to the external leader electrode 104. An upper electrode 106 is formed on the dielectric 105 including the hole 105a so as to electrically connect the upper electrode 106 and the external leader electrode 104 together. Subsequently, a protective layer 107 is formed at the top of these layers as required.
Thereby, as shown in FIG. 23(c), a capacitor is constructed in which the lower electrode 103 and the upper electrode 106 constitute a capacitance across the dielectric 105. In this case, a very thin capacitor can be constructed by using a thin flexible substrate 101 and thinning the lower electrode 103, the external leader electrode 104, the dielectric 105, the upper electrode 106, and others. Further, since the flexible substrate 101 is used, even if it is thin, the substrate is prevented from being disadvantageously damaged and broken.
Further, a capacitor having plural layers of dielectrics 105A and 105B and plural layers of upper electrodes 106A and 106B is manufactured, for example, as shown in FIGS. 24(a) to 24(d). First, as shown in FIG. 24(a), the lower electrode 103 and the external leader electrode 104 are formed so as to cover the opposite sides and top surface of the film-like very flexible substrate 101 and to have the gap 102 between themselves so that the electrodes 103 and 104 are not electrically connected together. Then, as shown in FIG. 24(b), a first dielectric 105A is formed on the top surface portions of the lower electrode 103 and the external leader electrode 104. Subsequently, a first upper electrode 106A is formed on the top surfaces of the first dielectric 105A and the external leader electrode 104. Further, a part of the first upper electrode 106A is formed so as to extend onto the external leader electrode 104 so that the first upper electrode is electrically connected to the external leader electrode 104. Then, as shown in FIG. 24(c), a second dielectric 100B is formed on the first upper electrode 106A. Furthermore, a second upper electrode 106B is formed on the second dielectric 105B. Further, a part of the second upper electrode 106B is formed so as to extend onto the lower electrode 103 so that the second upper electrode is electrically connected to the lower electrode 103. If more layers of dielectrics or upper electrodes are required, operations of forming these dielectrics or upper electrodes are repeated. Subsequently, the protective layer 107 is formed at the top of these layers as required.
Thus, as shown in FIG. 24(d), a capacitor is constructed in which the lower electrode 103 and the first and second upper electrodes 106A and 106B constitute a capacitance across the first and second dielectrics 105A and 105B. Also in this case, a very thin capacitor can be constructed by using the thin flexible substrate 101 and thinning the lower electrode 103, the external leader electrode 104, the dielectrics 105A and 105B, the upper electrodes 106A and 106B, and others.
Further, in another example, as shown in FIG. 25(a), a lower-electrode-connected external leader electrode 111 connected to the lower electrode 103 and an upper-electrode-connected external leader electrode 104 connected to the upper electrode 106 are formed so as to cover the opposite sides of the film-like flexible substrate 101. Then, a lower electrode 112 is formed so as to extend across the neighborhood of end surface portion of the lower-electrode-connected external leader electrode 111 and an external exposed surface of the flexible substrate 101. The lower electrode 112 is then connected to the lower-electrode-connected external leader electrode 111. Subsequently, as shown in FIG. 25(b), the dielectric 105 is formed on the top surfaces of the lower electrode 111 and the upper-electrode-connected external leader electrode 104 so as to extend across these electrodes. Then, the hole 105a is formed through the dielectric 105 at the position corresponding to the upper-electrode-connected external leader electrode 111. The upper electrode 106 is formed on the dielectric 105 including the hole 105a so as to electrically connect the upper electrode 106 and the external leader electrode 104 together. Subsequently, the protective layer 107 is formed at the top of these layers as required.
Thus, a capacitor is constructed in which the lower electrode 112 and the upper electrode 106 constitute a capacitance across the dielectric 105. Also in this case, a very thin capacitor can be constructed by using the thin flexible substrate 101 and thinning the lower-electrode-connected external leader electrode 111 and upper-electrode-connected external leader electrode 104, the lower electrode 112, the dielectric 105, the upper electrode 106, and others.
In this case, in a capacitor such as the one shown in FIG. 23, the wall surface of the hole portion 105a, formed in the dielectric 105, is formed substantially at a right angle (about 80 to 90xc2x0) to the flexible substrate 101 in order to connect the upper electrode 106 to the external leader electrode 104, as shown in the enlarged view of FIG. 26. Accordingly, corners 106a, 106b, 106c, and 106d of the upper electrode 106 formed along the hole portion 105a of the dielectric 105 are formed to be bent substantially at right angles.
Further, end surfaces of the lower electrode 103 and external leader electrode 104 which face each other via the gap 102 are formed substantially at right angles to the flexible substrate 101. Thus, the corners 105b, 105c, 105d, and 105e of the dielectric 105 and corners 106e, 106f, 106g, and 106h of the upper electrode 106, all of which are formed along the gap 102, are also formed to be bent substantially at right angles.
Further, in a capacitor such as the one shown in FIG. 24, end surfaces 105s and 105p of the first and second dielectrics 105A and 105B, respectively, are formed on the lower electrode 103 and the first upper electrode 106A so as to extend substantially at a right angle to these electrode, and are faced by downward extending portions 106i and 106j, respectively, extending downward from the first and second upper electrodes 106A and 106B to connect to the external leader electrode 104 and the lower electrode 103, as shown in the enlarged view of FIG. 27. Accordingly, corners 106k, 106m, 106n, and 106o of the upper and lower ends of the first and second upper electrodes 106A and 106B are formed to be bent substantially at right angles.
Further, in a capacitor such as the one shown in FIG. 25, an end surface 111a of the lower-electrode-connected external leader electrode 111 to which the lower electrode 112 is connected is formed substantially at a right angle to the flexible substrate 101, as shown in the enlarged view of FIG. 28. Corners 112a and 112b of the lower electrode 112 formed along the end surface 111a are formed to be bent substantially at right angles.
However, a capacitor using a flexible substrate 101 of this kind is advantageous in that its thickness can be significantly reduced, but it is likely to be deformed because of the use of the flexible substrate 101. Accordingly, if the capacitor undergoes relatively weak external stress (external force) when a thin product using this capacitor is vibrated or if stress is caused by a difference in expansion coefficient among the component materials in connection with temperature, then this stress is received by rigid metal material components. In particular, the stress may concentrate on the corners 106a to 106o, 112a, and 112b, bent at right angles, of the upper electrodes 106, 106A, and 106B and lower electrodes 103 and 112, all of which are thin.
If stress concentrates repeatedly on the upper electrodes 106, 106A, and 106B and the corners 112a and 112b of the lower electrode 112 to crack the capacitor, these cracks may develop to cut the capacitor or may narrow conductive portions. Consequently, when a relatively large current flows, the cracks may be widened to cut the capacitor. Further, in particular, if the upper electrodes 116, 116A, and 116B and the lower electrode 112 are formed by vapor deposition, then the corners 116a to 116o, 112a, 112b, and others tend to be thinner. As a result, this problem may become more serious.
To solve these problems, a capacitor as set forth in Aspect 1 of the present invention is characterized by comprising a flexible substrate, an upper-electrode-connected external leader electrode and a lower electrode formed on the flexible substrate with a gap between themselves so as not to be electrically connected together, a dielectric formed so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode, and an upper electrode arranged opposite the lower electrode across the dielectric, and in that a hole portion is formed through the dielectric so as to incline from a side that faces a bottom surface of the upper electrode to a side that faces the top surface of the external leader electrode, in that an inclined wall surface of hole portion of the dielectric is at least partly provided with a portion extending from a lower end to an upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode, and in that the upper electrode is formed to be depressed while inclining along the inclined wall surface of hole portion of the dielectric to connect to the top surface of the external leader electrode.
The invention as set forth in Aspect 2 is the capacitor as set forth in Aspect 1, wherein the inclined wall surface of hole portion of the dielectric is provided with a portion inclined downward from its upper end corner at an angle between 0.1 and 20xc2x0 and a portion inclined upward from its lower end corner at an angle between 0.1 and 20xc2x0.
The invention as set forth in Aspect 3 is the capacitor as set forth in claim 1 or 2, wherein the hole portion of the dielectric penetrates the dielectric in an inverted cone or pyramid form from a side that faces the upper electrode to a side that faces the external leader electrode.
The invention as set forth in Aspect 4 is the capacitor as set forth in any one of Aspects 1 to 3, wherein an inclined surface is formed on the upper electrode so as to incline along the inclined wall surface of hole portion of the dielectric, and the inclined surface of the upper electrode is at least partly provided with a portion extending from a lower end to a upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode.
The invention as set forth in Aspect 5 is the capacitor as set forth in Aspect 4, wherein the inclined surface of the upper electrode is provided with a portion inclined downward from its upper end corner at an angle between 0.1 and 20xc2x0 and a portion inclined upward from its lower end corner at an angle between 0.1 and 20xc2x0.
With the arrangements as set forth in Aspect 1 to 5, the inclined wall surface of hole portion of the dielectric is at least partly provided with the portion extending from the lower end to upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode. Accordingly, an inclined surface of the upper electrode which faces this portion is inclined gently at an angle close to 0.1 to 20xc2x0. This reduces stress concentration on this portion to prevent cracking.
Further, according to the arrangements as set forth in Aspect 2 and 5, the upper end corner of the inclined wall surface of hole portion of the dielectric has a downward inclination between 0.1 and 20xc2x0, and the lower end corner of the inclined wall surface of hole portion of the dielectric also has an upward inclination between 0.1 to 20xc2x0. Accordingly, the upper end corner of inclined wall surface of the upper electrode, which inclines along the hole portion of the dielectric, is gently inclined downward. Likewise, the lower end corner of inclined wall surface of the upper electrode, which inclines along the hole portion of the dielectric, is gently inclined upward. This reduces stress concentration on the above corners of the upper electrode to prevent the upper electrode from cracking.
A method of manufacturing a capacitor according to Aspect 6 of the present invention is characterized by comprising an external leader electrode and lower electrode forming step of forming an upper-electrode-connected external leader electrode and a lover electrode on a flexible substrate with a gap between themselves so that the electrodes viii not be electrically connected together, a dielectric forming step of forming a dielectric so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode, and a hole portion forming step of forming a hole portion through the dielectric at a position corresponding to the external leader electrode so that a wall surface of the hole portion at least partly inclines, the inclined wall surface being at least partly provided with a portion extending from its lower end to upper end at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode, and an upper electrode forming step of forming an upper electrode on the dielectric including the hole portion to electrically connect the upper electrode to the external leader electrode.
This method allows the capacitor as set forth in Aspect 1 to be manufactured appropriately.
The invention as set forth in Aspect 7 is the capacitor manufacturing method according to Aspect 6, wherein at the hole portion forming step, the hole portion is formed in the dielectric by allowing a plasma stream to pass through a hole in mask spaced at a predetermined distance from the dielectric.
The invention as set forth in Aspect 8 is the capacitor manufacturing method according to Aspect 6 or 7, wherein at the hole portion forming step; a spacer is interposed between the mask and the dielectric.
The invention as set forth in Aspect 9 is the capacitor manufacturing method according to Aspect 7, wherein at the hole portion forming step, the hole portion is formed in the dielectric by allowing a plasma stream to pass through the hole in the mask while moving the mask.
According to the capacitor manufacturing method as set forth in Aspects 7 to 9, the hole portion can be formed appropriately in the dielectric so as to be at least partly provided with the portion extending from the lower end to upper end of the dielectric at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode.
A capacitor as set forth in Aspect 10 of the present invention is characterized by comprising a flexible substrate, an upper-electrode-connected external leader electrode and a lower electrode formed on the flexible substrate with a gap between themselves so as not to be electrically connected together, a dielectric formed so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode, and an upper electrode arranged opposite the lower electrode across the dielectric, and in that a wall surface of the dielectric which is located above the external leader electrode is at least partly formed so as to incline downward from a side that faces a bottom surface of the upper electrode to a side that faces a top surface of the external leader electrode, in that the inclined wall surface of the dielectric is at least partly provided with a portion extending from a lower end to an upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode, and in that the upper electrode is formed to incline along the inclined wall surface of the dielectric so that its lover end is connected to the top surface of the external leader electrode.
The invention as set forth in Aspect 11 is the capacitor set forth in Aspect 10, wherein the inclined wall surface of the dielectric is provided with a portion inclined downward from its upper end corner at an angle between 0.1 and 20xc2x0 and a portion inclined upward from its lower end corner at an angle between 0.1 and 20xc2x0.
The invention as set forth in Aspect 12 is the capacitor as set forth in claim 10 or 11, wherein an inclined surface is formed on the upper electrode so as to incline along the inclined surface of the dielectric, and the inclined surface of the upper electrode is at least partly provided with a portion extending from a lower end to an upper end of the inclined surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode.
The invention as set forth in Aspect 13 is the capacitor as set forth in Aspect 12, wherein the inclined surface of the upper electrode is provided with a portion inclined downward from its upper end corner at an angle between 0.1 and 20xc2x0 and a portion inclined upward from its lover end corner at an angle between 0.1 and 20xc2x0.
With the arrangements as set forth in Aspects 10 to 13, the inclined wall surface of the dielectric is at least partly provided with the portion extending from the lower end to upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode. Further, the upper electrode is formed to incline along the inclined wall surface of the dielectric so that its lower end is connected to the top surface of the external leader electrode. Accordingly, the inclined surface of the upper electrode which corresponds to the gently inclined portion of the dielectric is inclined gently at an angle close to 0.1 to 20xc2x0. This reduces stress concentration on the inclined surface and corners of the upper electrode to prevent the upper electrode from cracking.
Further, according to the arrangements as set forth in Aspects 11 and 13, the dielectric is at least partly provided with the portion inclined downward from its upper end corner of inclined wall surface of a hole portion at an angle between 0.1 and 20xc2x0 and the portion inclined upward from its lower end corner of inclined wall surface of a hole portion at an angle between 0.1 and 20xc2x0. In this portion, the upper end corner of inclined wall surface of the upper electrode which inclines along the inclined wall surface of the dielectric is gently inclined downward. Likewise, the lower end corner of inclined wall surf ace of the upper electrode which inclines along the hole portion of the dielectric is gently inclined upward. This reduces stress concentration on the above corners of the upper electrode to prevent the upper electrode from cracking.
A method of manufacturing a capacitor according to Aspect 14 of the present invention is characterized by comprising an external leader electrode and lower electrode forming step of forming an upper-electrode-connected external leader electrode and a lower electrode on a flexible substrate with a gap between themselves so that the electrodes will not be electrically connected together, a dielectric forming step of forming a dielectric so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode, and an inclined wall surface forming step of forming an inclined wall surface on the dielectric at a position corresponding to the external leader electrode, the inclined wall surface being at least partly provided with a portion extending from a lower end to an upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode, and an upper electrode forming step of forming an upper electrode on the dielectric including the inclined wall surface and electrically connecting the upper electrode and the external leader electrode together.
This method allows the capacitor set forth in Aspects 10 to 13 to be manufactured appropriately.
A capacitor as set forth in Aspect 15 of the present invention is characterized by comprising a flexible substrate, an upper-electrode-connected external leader electrode and a lower electrode formed on the flexible substrate with a gap between themselves so as not to be electrically connected together, and a plurality of upper electrodes formed above the lower electrode via respective dielectrics as a plurality of layers and each connected to the external leader electrode or the lower electrode via an inclined downward extending portion extending to the external leader electrode or the lower electrode and via a connecting section, and in that that wall surface of the dielectric located immediately below each upper electrode which faces the inclined downward extending portion is formed to incline downward from a side that faces a bottom surface of the upper electrode to a side that faces a top surface of the external leader electrode or the lower electrode, and in that the inclined wall surface of each of the dielectrics is at least partly provided with a portion extending from a lower end to an upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surfaces of the external leader electrode and the lower electrode.
The present invention as set forth in Aspect 16 is the capacitor as set forth in Aspect 15, wherein the inclined wall surface of each dielectric is at least partly provided with a portion inclined downward from its upper end corner at an angle between 0.1 and 20xc2x0 and a portion inclined upward from its lower end corner at an angle between 0.1 and 20xc2x0.
The invention as set forth in Aspect 17 is the capacitor as set forth in claim 15 or 16, wherein the inclined downward extending portion of each upper electrode is at least partly provided with a portion extending from a lower end to an upper end of the inclined downward extending portion at an inclination between 0.1 and 20xc2x0 with respect to the top surfaces of the external leader electrode and the lower electrode.
The invention as set forth in Aspect 18 is the capacitor set forth in Aspect 17, wherein the inclined downward extending portion of each upper electrode is provided with a portion inclined downward from its upper end corner at an angle between 0.1 and 20xc2x0 and a portion inclined upward from its lower end corner at an angle between 0.1 and 20xc2x0.
According to the arrangements as set forth in Aspects 15 to 18, the inclined wall surface of each of the dielectrics is at least partly provided with the portion extending from the lower end to upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surfaces of the external leader electrode and the lower electrode. Accordingly, the inclined surface of the upper electrode which corresponds to the gently inclined portion of each dielectric is also inclined gently at an angle between 0.1 and 20xc2x0. This reduces stress concentration on the inclined surface and corners of the upper electrode to prevent the upper electrode from cracking.
Further, according to the arrangements am set forth in Aspects 16 and 18, the inclined wall surface of each dielectric is at least partly provided with the portion inclined downward from its upper end corner at an angle between 0.1 and 20xc2x0 and the portion inclined upward from its lower end corner at an angle between 0.1 and 20xc2x0. In this portion, the upper end corner of inclined wall surface of the upper electrode, inclining along the inclined wall surface of the dielectric, is gently inclined downward. Likewise, the lower end corner of inclined wall surface of the upper electrode, inclining along the inclined wall surface of the dielectric, is gently inclined upward. This reduces stress concentration on the above corners of the upper electrode to prevent the upper electrode from cracking.
A method of manufacturing a capacitor according to Aspect 19 is characterized by comprising an external leader electrode and lower electrode forming step of forming an upper-electrode-connected external leader electrode and a lover electrode on a flexible substrate with a gap between themselves so that the electrodes will not be electrically connected together, a dielectric and upper electrode forming step of forming a plurality of upper electrodes above the lower electrode via respective dielectrics as a plurality of layers and connecting each of the upper electrodes to the external leader electrode or the lower electrode via an inclined downward extending portion extending to the external leader electrode or the lower electrode and via a connecting section, and in that at the dielectric and upper electrode forming step, an inclined wall surface of the dielectric is formed so that that wall surface of the dielectric located immediately below each upper electrode which faces the inclined downward extending portion inclines downward from a side that faces a bottom surface of the upper electrode to a side that faces a top surface of the external leader electrode or the lover electrode and so that the inclined wall surface of each of the dielectrics is at least partly provided with a portion extending from a lower end to an upper end of the inclined wall surface at an inclination between 0.1 and 20xc2x0 with respect to the top surfaces of the external leader electrode and the lower electrode.
This method allows the capacitor as set forth in Aspects 15 to 18 to be manufactured appropriately.
The invention as set forth in Aspect 20 is the capacitor manufacturing method according to Aspect 14 or 19, wherein at the step of forming the inclined wall surface of the dielectric, sputtering is carried out with a predetermined space provided between the mask and the dielectric.
The invention as set forth in Aspect 21 is the capacitor manufacturing method according to Aspect 20, wherein at the step of forming the inclined end wall surface of the dielectric, a spacer is interposed between the mask and the dielectric.
The invention as set forth in Aspect 22 is the capacitor manufacturing method according to Aspect 20, wherein at the step of forming the inclined end wall surface of the dielectric, sputtering is carried out while moving the mask.
According to the capacitor manufacturing method as set forth in Aspects 20 to 22, the inclined end wall surface can be formed appropriately in the dielectric so as to be at least partly provided with the portion extending from the lower end to upper end of the inclined surf ace of the dielectric at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the external leader electrode.
A capacitor as set forth in Aspect 23 of the present invention is characterized by comprising a flexible substrate, an upper-electrode-connected external leader electrode and a lower electrode formed on the flexible substrate with a gap between themselves so as not to be electrically connected together, a dielectric formed so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode, an upper electrode arranged opposite the lower electrode across the dielectric and electrically connected to the external leader electrode, and an insulator that fills the gap between the external leader electrode and the lover electrode, and in that the dielectric is formed to also cover the insulator.
The invention as set forth in Aspect 24 is the capacitor as set forth in Aspect 23, wherein of layers formed over the insulator filling the gap between the external leader electrode and the lower electrode, portions that contact with the top surfaces of the external leader electrode and lower electrode at least partly have an inclination of xc2x120xc2x0.
According to the arrangements as set forth in Aspects 23 and 24, the insulator fills the gap between the lower electrode and the external leader electrode. Accordingly, no corners are created in areas of the dielectric and upper electrode which correspond to the gap, or the corners are gently inclined. This eliminates or reduces stress concentration on the corners to prevent the upper electrode from cracking.
A method of manufacturing a capacitor according to Aspect 25 of the present invention is characterized by comprising an external leader electrode and lower electrode forming step of forming an upper-electrode-connected external leader electrode and a lower electrode on a flexible substrate with a gap between themselves so that the electrodes will not be electrically connected together, a gap filling step of using an insulator to fill a gap between the external leader electrode and the lover electrode, a dielectric forming step of forming a dielectric so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode and across a top surface of the insulator, and an upper electrode forming step of forming an upper electrode on the dielectric and electrically connecting the upper electrode to the external leader electrode.
This method allows the capacitor as set forth in Aspects 23 and 24 to be manufactured appropriately.
A capacitor as set forth in Aspect 26 of the present invention is characterized by comprising a flexible substrate, an upper-electrode-connected external leader electrode and a lower electrode formed on the flexible substrate with a gap between themselves so as not to be electrically connected together, a dielectric formed so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode, and an upper electrode arranged opposite the lower electrode across the dielectric and electrically connected to the external leader electrode, and in that each end surface facing the gap between the external leader electrode and the lower electrode is formed to incline relative to a top surface of the flexible substrate, in that an inclined end surface of the external leader electrode and an inclined end surface of the lower electrode are each at least partly provided with a portion extending from a lower end to an upper end of the inclined end surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the flexible substrate, and in that a dielectric and the upper electrode are formed along the inclined end surfaces of the external loader electrode and the lower electrode.
According to this arrangement, each end surface facing the gap between the external leader electrode and the lower electrode is formed to incline relative to the top surface of the flexible substrate. Further, the inclined end surface of the external leader electrode and the inclined end surface of the lower electrode are each at least partly provided with the portion extending from the lower end to upper end of the inclined end surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the flexible substrate. Furthermore, the dielectric and the upper electrode are formed along the inclined end surfaces of the external leader electrode and lower electrode. Accordingly, the corner of the dielectric corresponding to the gap and the corner of the upper electrode disposed over the gap are inclined gently. This reduces stress concentration on the corners to prevent the upper electrode from cracking.
A method of manufacturing a capacitor according to Aspect 27 of the present invention is characterized by comprising an external leader electrode and lower electrode forming step of forming an upper-electrode-connected external leader electrode and a lower electrode on a flexible substrate with a gap between themselves so that the electrodes will not be electrically connected together, a dielectric forming step of forming a dielectric so as to extend across a top surface of the external leader electrode and a top surface of the lower electrode, and an upper electrode forming step of forming an upper electrode on the dielectric and electrically connecting the upper electrode to the external leader electrode, and in that at the external leader electrode and lower electrode forming step, each end surface facing the gap between the external leader electrode and the lower electrode is formed to incline relative to a top surface of the flexible substrate, in that in this case, an inclined end surface of the external leader electrode and an inclined end surface of the lower electrode are each at least partly provided with a portion extending from a lower end to an upper end of the inclined end surface at an inclination between 0.1 and 20xc2x0 with respect to the top surface of the flexible substrate, and in that the dielectric and the upper electrode are formed along the inclined end surfaces of the external leader electrode and the lower electrode.
This method allows the capacitor as set forth in Aspect 26 to be manufactured appropriately.
A capacitor as set forth in Aspect 28 of the present invention is characterized by comprising a flexible substrate, an upper-electrode-connected external leader electrode and a lower electrode formed on the flexible substrate with a gap between themselves so as not to be electrically connected together, insulators filled into two respective corners so that their wall surfaces are inclined, each of the two corners being located between an end surface portion of the external leader electrode or lower electrode which faces the gap and an area of the flexible substrate which is close to the end surface portion, each of the insulators being at least partly provided with a portion extending from a lower end to an upper end of an inclined surface of the insulator and having an inclination between 0.1 and 20xc2x0 with respect to a top surface of the flexible substrate and an inclination of xc2x120xc2x0 with respect to top surfaces of the external leader electrode and the lower electrode, a dielectric formed so as to extend across the top surfaces of the external leader electrode and the lover electrode and across the inclined surfaces of the insulators, and an upper electrode arranged opposite the lower electrode across the dielectric and electrically connected to the external leader electrode.
According to this arrangement, the insulators are filled into the two respective corners so that their wall surfaces are inclined, each of the two corners being located between the end surface portion of the external leader electrode or lower electrode which faces the gap and the area of the flexible substrate which is close to the end surface portion. Further, each of the insulators is at least partly provided with the portion extending from the lower end to upper end of the inclined surface of the insulator and having an inclination between 0.1 and 20xc2x0 with respect to a top surface of the flexible substrate and an inclination of xc2x120xc2x0 from top surfaces of the external leader electrode and lower electrode. Accordingly, the corner of the dielectric corresponding to the gap and the corner of the upper electrode disposed over the gap are inclined gently. This reduces stress concentration on the corners to prevent the upper electrode from cracking.
A method of manufacturing a capacitor according to Aspect 29 of the present invention is characterized by comprising an external leader electrode and lower electrode forming step of forming an upper-electrode-connected external leader electrode and a lower electrode on a flexible substrate with a gap between themselves so that the electrodes will not be electrically connected together, an insulator filling step of filling insulators into two respective corners so that their wall surfaces are inclined, each of the two corners being located between an end surface portion of the external leader electrode or lower electrode which faces the gap and an area of the flexible substrate which is close to the end surface portion, the insulator being at least partly provided with a portion extending from a lower end to an upper end of an inclined surface of the insulator and having an inclination between 0.1 and 20xc2x0 with respect to a top surface of the flexible substrate and an inclination of xc2x120xc2x0 with respect to top surfaces of the external leader electrode and lower electrode, a dielectric forming step of forming a dielectric so as to extend across the top surfaces of the external leader electrode and the lower electrode and across the inclined surfaces of the insulators, and an upper electrode forming step of forming an upper electrode on the dielectric and electrically connecting the upper electrode to the external leader electrode.
This method allows the capacitor as set forth in Aspect 28 to be manufactured appropriately.
A capacitor as set forth in Aspect 30 of the present invention is characterized by comprising a flexible substrate, a lower-electrode-connected external leader electrode formed on the flexible substrate, an upper-electrode-connected external leader electrode formed on the flexible substrate, an insulator filled into a corner of the flexible substrate which faces an end surface portion of the lower-electrode-connected external leader electrode, the insulator being at least partly provided with a portion extending from a lower end to an upper end of an inclined surface of the insulator and having an inclination between 0.1 and 20xc2x0 with respect to a top surface of the flexible substrate and an inclination of xc2x120xc2x0 with respect to a top surface of the lower-electrode-connected external, leader electrode, a lower electrode formed so as to extend across a neighborhood of the end surface portion of the lower-electrode-connected external leader electrode, the inclined surface of the insulator, and an external exposed surface of the flexible substrate, a dielectric formed on the lower electrode, and an upper electrode arranged opposite the lover electrode across the dielectric and electrically connected to the upper-electrode-connected external leader electrode.
According to this arrangement, the insulator is filled into the corner of the flexible substrate which faces the end surface portion of the lover-electrode-connected external leader electrode, the insulator being at least partly provided with the portion extending from the lover end to upper end of the inclined surface of the insulator and having an inclination between 0.1 and 20xc2x0 with respect to the flexible substrate and an inclination of xc2x1200 with respect to the top surface of the lower-electrode-connected external leader electrode. Accordingly, the corner of the lover electrode corresponding to the gap is inclined gently. This reduces stress concentration on the corners to prevent the lover electrode from cracking.
A method of manufacturing a capacitor according to Aspect 31 is characterized by comprising a lover-electrode-connected external leader electrode forming step of forming a lower-electrode-connected external leader electrode on a flexible substrate, an upper-electrode-connected external leader electrode forming step of forming an upper-electrode-connected external leader electrode on the flexible substrate, an insulator forming step of forming an insulator in a corner between an end surface portion of the lower-electrode-connected external leader electrode and an area of the flexible substrate which is close to the end surface portion, the insulator being formed so that its end surface is inclined at an angle between 0.1 and 20xc2x0 with respect to the flexible substrate, an insulator forming step of filling an insulator into a corner of the flexible substrate which faces the end surface portion of the lower-electrode-connected external leader electrode, the insulator being at least partly provided with a portion extending from a lower end to an upper end of an inclined surface of the insulator and having an inclination between 0.1 and 20xc2x0 with respect to a top surface of the flexible substrate and an inclination of xc2x120xc2x0 with respect to a top surface of the lower-electrode-connected external leader electrode, a lover electrode forming step of forming a lower electrode so as to extend across a neighborhood of the end surface portion of the lower-electrode-connected external leader electrode, the inclined surface of the insulator, and an external exposed surface of the flexible substrate, a dielectric forming step of forming a dielectric on the lower electrode, and an upper electrode forming step of forming an upper electrode arranged opposite the lower electrode across the dielectric and electrically connected to the upper-electrode-connected external leader electrode.
This method allows the capacitor as set forth in Aspect 30 to be manufactured appropriately.
The invention as set forth in Aspect 32 is the capacitor as set forth in any of Aspect 23, 24, 28, and 30, wherein the insulator is a resin.
The invention as set forth in Aspect 33 is the capacitor as set forth in any of Aspects 1 to 5, 11 to 15, 21, 22, 24, 26, 28, and 29, wherein the dielectric is formed of a material selected from a group consisting of polyphenylene sulfide, silicon dioxide, divinylbenzene polymer, strontium titanate, syndiotactic polystyrene, cyclic olefin copolymer film, polyphenylene oxide, polybenzocyclobutene polymer, divilnaphthalene polymer, divinylbiphenyl polymer, aluminum oxide, and polyetheretherketone resin, and mixtures of any of these materials.
The invention as set forth in Aspect 34 is the capacitor as set forth in any of Aspects 1 to 5, 10 to 13, 15 to 18, 23, 24, 26, 28, 30, and 32, wherein the flexible substrate is a resin film.
The invention as set forth in Aspect 35 is the capacitor manufacturing method as set forth in any of Aspects 6 to 9, 14, 19 to 22, 25, 27, 29, and 31, wherein at the dielectric forming step, the dielectric is formed by sticking a film-like dielectric.
The invention as set forth in Aspect 36 is the capacitor manufacturing method as set forth in any of Aspects 6 to 9, 14, 19 to 22, 25, 27, 29, and 31, wherein at the dielectric forming step, the dielectric is formed by vapor deposition.
The invention as set forth in Aspect 37 is the capacitor manufacturing method as set forth in Aspect 8 or 21, wherein the spacer is formed of polyethylene terephthalate or polyethylene naphthalate or a mixture of these materials.